With a tiny clump of cells from a man's scalp, scientists have grown new human hair in the laboratory.

But don't get too excited. A magic cure for baldness isn't around the corner. The experimental approach is quite limited and years from reaching the clinic — for many reasons.

The scientists have grown the hair only on a tiny patch of human skin grafted onto the back of a mouse. And as wispy locks go, the strands are pretty pathetic. Some hairs were white, and some didn't even make their way out of the skin.

Nevertheless, the proof-of-concept study, reported Monday in the Proceedings of the National Academy of Sciences, overcame a major obstacle to increasing the quantity of hair on your head.

Currently, people with hair loss have two options: drugs and surgical transplantation. "The drugs available work reasonably well at maintaining the hair you have," says Angela Christiano, a professor of dermatology at Columbia University Medical Center who led the study. "And with transplantation, you can move hair around the head, like from front to back. But neither [method] is known for being a way to actually grow new hair."

For that, scientists needed a way to make new hair follicles.

All human hair grows inside follicles, which are little tubes. When you're a baby developing inside the womb, cells in the skin decide where to put the follicles — and thus, your hair. Follicles go on legs, arms and head. But you don't get any on your palms, the soles of your feet and a few other places.

Once you're born, this pattern of hair doesn't change. The follicles may decide to go kaput later in life or start producing peach fuzz, as with male pattern baldness. But your skin never makes new follicles.

That's where Christiano and her team at Columbia University have made progress. Working together with Colin Jahoda in Durham University in England, they figured out a way to trick adult skin into growing new follicles and eventually new hair.

They took a special type of skin cell from seven men with male pattern baldness and grew them up in a Petri dish. Previous studies had just let the cells replicate on a 2D surface, but Christiano and her colleagues coerced the cells into clumping together and forming little balls. That slight variation made all the difference in the world.

The team put the spheres of cells inside a patch of human skin and grafted it onto a mouse. Six weeks later, the cells grew whole new hair follicles and tiny wisps of hair. The procedure worked in five of the seven men tested.

But the hair follicles weren't normal. They were missing sebaceous glands that keep the skin moist. And the hair grew out of the skin at funny angles.

"Before we can move into clinical trials, the procedure would have to be animal-free," Christiano says. "And we need much more hairs than we have. But conservatively, I'd love to have the method in clinical trials in three to five years."

Other scientists in the field are a bit more cautious.

"You can ask anyone how long it will take something in the future to happen, and the answer will always be three to five years," says Luis Garza, a dermatologist at Johns Hopkins University who wasn't involved in the study.

"Any time you grow cells in the laboratory and inject them back inside people, there's a chance the cells could overgrow," Garza tells Shots. That means the cells could form tumors or even some cancers. Plus, a technique like this, Garza speculates, would be much more expensive than regular hair transplantation.

Nevertheless, the findings are a major advance in the field, he says. "Before this method goes into clinical trials, we've got a mountain climb,and it's miles of steep terrain ahead," he says. "But the findings of Dr. Christiano definitely get us closer."